"It doesn't affect their work," he said. "You don't really see it that much."

And, though Sam's changeling character Sam Merlotte pines for Paquin's character Sookie Stackhouse and is jealous of Moyer's vampire Bill Compton on the show, there's only happy wishes for the real-life couple.

"I think they're both just really independent, really talented people, and they just kind of fit together," Trammell says.

"They've been together a long time, and it's working out," he says. "I'm happy for them."